Absorbable multi-putty bone cements and hemostatic compositions and methods of use

ABSTRACT

The present invention relates to absorbable polyurethane compositions suitable for use in bone repair or reconstruction. The present invention relates to the field of polyurethane-based cements, and putties for use in bone hemostasis, repair and reconstruction. The putty compositions may comprise a mixture of two or more individual putties formed through mixing of one or more reactive components and one or more additive (filler) components. Also disclosed herein are methods of using the putty compositions in medical applications to repair gaps or fractures, or to aid in tissue growth or adhesion.

FIELD OF THE INVENTION

The present invention relates to the field of implantable polymericcompositions for medical use in a patient to aid in repair orreconstruction of tissue, such as bone. Specifically to the field ofpolyurethane-based cements, and putties for use in bone hemostasis,repair and reconstruction. The putty compositions may comprise a mixtureof two or more individual putties (multi-putty) formed through mixing ofone or more reactive components and one or more additive (filler)components. Also disclosed herein are methods of using the puttycompositions in medical applications to repair gaps or fractures, or toaid in tissue growth or adhesion. In particular, the subject matterherein provides a putty composition that is formed from two or moreindividual putties that are obtained by mixing a liquid component and afiller component.

INCORPORATION BY REFERENCE

Each of the applications and patents cited in this text, as well as eachdocument or reference cited in each of the applications and patents(including during the prosecution of each issued patent; “applicationcited documents”), and each of the U.S. and foreign applications orpatents corresponding to and/or claiming priority from any of theseapplications and patents, and each of the documents cited or referencedin each of the application cited documents, are hereby expresslyincorporated herein by reference. More generally, documents orreferences are cited in this text, either in a Reference List before theclaims, or in the text itself; and, each of these documents orreferences (“herein-cited references”), as well as each document orreference cited in each of the herein-cited references (including anymanufacturer's specifications, instructions, etc.), is hereby expresslyincorporated herein by reference. Documents incorporated by referenceinto this text may be employed in the practice of the invention.

BACKGROUND OF THE INVENTION

Bone cements are used surgically to assist in the attachment ofartificial implants to living bone and for bone repair andreconstruction. The most commonly used bone cements comprise polymersformed from a mixture of polymethylmethacrylate (PMMA) and a monomer,such as methylmethacrylate (MMA), reacting in the presence of apolymerization activator or reaction initiator. These conventionalPMMA-based cements have several disadvantages. Typically, the excessiveexotherm during the curing process of conventional cements may itselfcause tissue damage. In addition, conventional cements are not easilydegradable or absorbable in vivo. This may present both an increasedrisk of infection and/or an inflammatory reaction at the site and mayinhibit the growth of new bone at the site.

Biodegradable polymers have become increasingly important for a varietyof biomedical applications including biomedical implants, such assutures, stents, and coatings applied to those implants, tissueengineering scaffolds, and soft-tissue adhesives. Segmented polyurethaneelastomers in particular have come into wide use as biomaterials due totheir superior mechanical properties and chemical versatility. PCTInternational Application Publication No. WO 2004009227 describescertain degradable polyurethane compositions for use as tissueengineering scaffolds. U.S. Pat. No. 6,306,177 by Felt, et al.,describes certain degradable polyurethanes for in situ tissue repair.U.S. Patent Application Publication No. 20050013793 by Beckman, et al.,also describes degradable polyurethanes for e.g., tissue engineering andparticularly for bone repair and replacement. U.S. Pat. No. 4,829,099 byFuller, et al., describes certain absorbable polyisocyanates for use assurgical adhesives. U.S. Pat. Nos. 8,002,843 and 7,985,414 by Knaack, etal., describe a biodegradable polyisocyanate (such as lysinediisocyanate) with an optionally hydroxylated biomolecule to form adegradable polyurethane. U.S. Pat. No. 7,964,207 by Deslaurier, et al.,describes porous, non-absorbable, osteoconductive polyurethanecompositions having mechanical properties consistent for use in bonerepair.

For the preparation of implantable polyurethanes, it is conventional tomix, in the operating room, pre-weighed amounts of a diisocyanate, apolyol, a chain extender and, optionally, a filler that is oftenceramic-like, polymeric or a cellulosic material. Optionally, anantimicrobial agent, e.g., tobramycin, may be added to reduce theincidence of post-operative infection. The components are usually liquidat ambient temperature and require mixing liquids and, sometimes,liquids with solids in a suitable container using a suitable stirringmechanism.

Liquid component settable polymers (e.g., Kryptonite) in medical usetraditionally require mixing and application of the activated polymer asa liquid. Polymers provided in this way are difficult to apply, maybecome slippery upon exposure to body fluids, stick to surgical gloves,instruments and fixation devices such as wires, plates and screws. Insome instances, polymer misapplication may result in damage to medicaldevices, such as drains and catheters, during their removal.

Despite progress in the development of polyurethane-based biomedicalmaterials, there remains a need for non-toxic, readily biodegradable orabsorbable compositions having suitable mechanical properties for bonerepair and reconstruction. The present invention providespolyurethane-based compositions suitable for use in bone repair andreconstruction, specifically as bone cements, bone substitutes orhemostatic agents.

SUMMARY OF THE INVENTION

The present invention provides curable, absorbable polyurethane andpolyureaurethane compositions comprising a polyaromatic polyisocyanateand one or more polyols and/or polyamines. Preferably, the compositionis provided in binary form, more specifically in the form of two puttieswhich, when mixed or kneaded together form a settable hemostatic agent,bone substitute or cement. As used herein the term “putty” refers tosoft moldable, preferably non-elastic, cohesive compositions, most oftenformed as viscous suspensions or dispersions of particulates within aliquid. The inventive putties may also be formed from monolithiccompositions of waxes and soft polymers: The putties of the inventionare distinguished from the transitional “taffy” phases which occurduring the setting process of polyurethanes and other settablecompositions. Accordingly, in one embodiment, the present inventionprovides a binary package or article of manufacture comprising a firstcomponent and a second component, wherein the first component contains acurable polyaromatic di- or polyisocyanate having a hydrolysable linkagebridging at least two of the aromatic rings and the second componentcontains a polyol or polyamine, or mixtures thereof. In anotherembodiment, the invention provides a binary package or article ofmanufacture comprising a first component and a second component, whereinthe first component contains a curable prepolymer of a polyaromaticpolyisocyanate having a hydrolysable linkage bridging at least two ofthe aromatic rings and a polyol in the form of a putty and the secondcomponent, also in the form of a putty, containing an isocyanate, anabsorbable polyol, a chain extender and none, or one or more additives.In another embodiment, the invention provides a curable, absorbablepolymeric composition formed by the reaction of two or more individualputty compositions, wherein a first putty composition comprises one ormore reactive components and one or more additive components and asecond putty composition comprises one or more reactive components andone or more additive components. Preferably, the one or more reactivecomponents in the first putty composition comprise an isocyanate and/ormixtures of isocyanates, and most preferably the isocyanate is[5-[2-[2-(4-isocyanatobenzoyl)oxypropanoyloxy]-ethoxy]-1-methyl-2-oxo-pentyl]-4-isocyanatobenzoate(ALD). Also preferred is an embodiment in which the second puttycomprises one or more polyols, hydroxyl terminated polymers ofglycolide, lactide, p-dioxanone, trimethylene carbonate and/orcaprolactone, polyethylene glycol, a copolymer of ethylene oxide andpropylene oxide (poloxamers), 1,2-ethanediol (ethylene glycol),1,2-propanediol (propylene glycol), 1,3-propanediol, 1,4-butanediol,1,5-pentanediol, 1,3-cyclopentanediol, 1,6-hexanediol,1,4-cyclohexanediol, 1,8-octanediol, glycerol, polyethylene glycol andpolypropylene glycol with molecular weights of 400-10000, andcombinations thereof. In accordance with the above embodiments, the oneor more additive components in each individual reactive puttycomposition may comprise a carbonate or bicarbonate selected fromcalcium carbonate, magnesium carbonate, aluminum carbonate, ironcarbonate, zinc carbonate, calcium bicarbonate, sodium bicarbonate,embedded particles of bone, demineralized bone, bone morphogeneticprotein, hydroxyapatite, calcium phosphate, siliconized calciumphosphate, absorbable phosphate glass, an inorganic material, a bonesubstitute material, a carbonate selected from magnesium carbonate,aluminum carbonate, iron carbonate, zinc carbonate, calcium carbonate,sodium carbonate, and a bicarbonate of magnesium, aluminum, iron, orzinc, and combinations thereof. In one embodiment, the one or morereactive components in the second putty composition comprises apolyurethane formed from one or more polyols reacted with isocyanate. Inaccordance with any of these embodiments, the composition may furthercomprise one or more putties in addition to the two putties of thebinary composition.

The polyurethane compositions of the invention are formed from thereaction of a polyaromatic polyisocyanate, one or more polyols and/orpolyamines and, optionally, a polyol and/or a polyamine as a chainextender. Thus, as used throughout the present disclosure with referenceto the compositions of the invention, the term “comprising” refers tothe polyurethane or polyureaurethane reaction product of an isocyanate,a polyol/polyamine and, optionally, a polyol and/or a polyamine as achain extender.

The polyurethane compositions of the invention are low exotherm,biocompatible compositions suitable for use in vivo, particularly as abone cement or hemostatic agent during bone repair and reconstructivesurgery. For example, the curable, moldable polyurethane compositions ofthe invention are well-suited for use in the repair of cranial defectsand cranioplasty applications as well as for repair and reconstructionof the sternum. The term nontoxic as used herein refers to thebiocompatibility of the polyurethane compositions of the invention. Thecompositions of the invention are absorbable, in part due to ahydrolysable linkage bridging the aromatic rings. In certainembodiments, the hydrolysable linkage is derived from glycolic acid,lactic acid, caprolactone, or p-dioxanone. Both the curable polyurethanecompositions of the invention and their degradation products arebiocompatible. Unlike certain prior art aromatic isocyanates, thepresent compositions do not degrade into toxic byproducts such as, forexample, aromatic diamines.

In certain embodiments, curable, absorbable polyurethane andpolyureaurethane compositions of the invention further comprise one ormore hydrolysable polyols and/or polyamines. In one embodiment, thepolyol is selected from hydroxyl terminated copolymers of glycolide,lactide, p-dioxanone, trimethylene carbonate and/or caprolactone,polyethylene glycol, a copolymer of ethyelene oxide and propylene oxide(Pluronic). In another embodiment, the polyol is selected from apolycaprolactone co-glycolide or a polycaprolactone co-lactide, orcombinations thereof.

The polyurethane and polyureaurethane compositions of the invention mayfurther comprise one or more chain extenders or crosslinkers. In oneembodiment, the curable, absorbable polyurethane and polyureaurethanecompositions of the invention are crosslinked. In another embodiment,the curable, absorbable polyurethane and polyureaurethane compositionsof the invention are not crosslinked. In one embodiment, the one or morechain extenders or crosslinkers is selected from a natural or syntheticaliphatic polyol. In one embodiment, the composition is formed by aprocess that includes one or more chain extenders selected from1,2-ethanediol (ethylene glycol), 1,2-propanediol (propylene glycol),1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,3-cyclopentanediol,1,6-hexanediol, 1,4-cyclohexanediol, 1,8-octanediol, glycerol,polyethylene glycol and polypropylene glycol with molecular weights of500-10000, and combinations thereof.

In one embodiment, the curable, absorbable polyurethane compositions ofthe invention comprise a glycolide linked diisocyanate and apolycaprolactone-co-glycolide polyol. In one embodiment, the compositionfurther comprises butanediol, e.g., as a chain extender. In oneembodiment, the composition further comprises one or more of water, acarboxylic acid, e.g., benzoic acid, and a divalent or polyvalent metalsalt.

In one embodiment, the curable, absorbable polyurethane compositions ofthe invention comprise a lactide linked diisocyanate and apolycaprolactone-co-glycolide polyol. In one embodiment, the compositionfurther comprises butanediol, e.g., as a chain extender. In oneembodiment, the composition further comprises one or more of water, acarboxylic acid, e.g., benzoic acid, and a divalent or polyvalent metalsalt.

In one embodiment, the curable, absorbable polyurethane compositions ofthe invention comprise a tetraisocyanate. In one embodiment, thetetraisocyanate is a caprolactone ethylene glycol linked phenylalaninediisocyante. In one embodiment, the composition further comprises one ormore of water, a carboxylic acid, e.g., benzoic acid, and a divalent orpolyvalent metal salt.

In one embodiment, the curable, absorbable polyurethane andpolyureaurethane compositions of the invention further comprise one ormore particulate materials. In one embodiment, the one or moreparticulate materials is present in an amount that is up to about 80% ofthe composition by weight. In one embodiment, the one or moreparticulate materials is a carbonate or bicarbonate selected fromcalcium carbonate, magnesium carbonate, aluminum carbonate, ironcarbonate, zinc carbonate, calcium bicarbonate, and sodium bicarbonate.In one embodiment, the one or more particulate materials do not comprisecalcium carbonate or calcium phosphate. In one embodiment, the one ormore particulate materials is selected from embedded particles of bone,demineralized bone, bone morphogenetic protein, hydroxyapatite, calciumphosphate, siliconized calcium phosphate, absorbable phosphate glass, aninorganic material, a bone substitute material, a carbonate selectedfrom magnesium carbonate, aluminum carbonate, iron carbonate, zinccarbonate, calcium carbonate, sodium carbonate, and a bicarbonate ofmagnesium, aluminum, iron, or zinc, or a combination of any of theforegoing. In one embodiment, the compositions of the invention do notcomprise a particulate material. Other possible additives are starch,carboxymethyl starch, carboxymethyl cellulose, oxidized cellulose,antimicrobial agents, colorants, X-ray opaque substances and water (iffoaming is desired).

In general, the curable, absorbable polyurethane and polyureaurethanecompositions of the invention are formed by the reaction of one or morepolyaromatic di- or poly-isocyanates with one or more diols or polyolsand/or polyamines. The process for forming the polyurethane andpolyureaurethane compositions of the invention may also include theaddition of an optional chain extender or crosslinker. In oneembodiment, the compositions of the invention are formed in the absenceof a crosslinker. In one embodiment, the composition is formed by aprocess of combining a polyol and/or a polyamine, a polyaromatic di- orpoly-isocyanate, and a carboxylic acid. In one embodiment, thecarboxylic acid is selected from benzoic acid, malic acid, and succinnicacid. In another embodiment, the composition is formed by a process ofcombining a polyol and/or polyamine, a polyaromatic polyisocyanate, andwater.

In another embodiment, the package or article of manufacture comprises afirst component and a second component wherein the first componentcontains a curable polyaromatic di- or polyisocyanate having at leastone hydrolysable linkage bridging at least two of the aromatic rings andis in the form of putty-like consistency while the second componentcontains a polyol and/or a polyamine, also in the form of putty-likeconsistency. In this embodiment, the putties of the first and of thesecond component are mixed or kneaded together at the time of use toform a settable hemostatic agent or bone void filler or bone cement. Incomponent 1, a small amount of polyol may be added to form a putty-likeprepolymer while a small amount of isocyanate may be added to component2 to form a putty-like polyol derivative. Other additives such as chainextenders, catalysts, cross-linking agents and bulking agents such ascalcium phosphate, etc., also may be added to component 2.

The invention also provides a package or article of manufacturecontaining the polyurethane or polyureaurethane composition of claim 1in its fluid form, wherein the package or article is maintained at atemperature below 0 C. In another embodiment, the invention provides abinary package or article of manufacture comprising a first componentand a second component, wherein the first component contains a curablepolyaromatic di- or polyisocyanate having a hydrolysable linkagebridging at least two of the aromatic rings and the second componentcontains a polyol and/or a polyamine. In another embodiment, the binarypackage or article of manufacture comprises a first component and asecond component, wherein the first component contains a curableprepolymer of a polyaromatic di- or polyisocyanate having a hydrolysablelinkage bridging at least two of the aromatic rings and a polyol and/orpolyamine and the second component contains a chain extender. In certainembodiments, the components of the package or article of manufacture aresterile or sterilizable.

The invention further provides methods for applying the compositions ofthe invention to a surface. In one embodiment, the method comprises asingle step of applying a curable polyurethane or polyureaurethanecomposition of the invention to the surface, with or without a catalyst.In another embodiment, the method comprises mixing anisocyanate-terminated prepolymer of the compositions of the inventionwith the polyol/polyamine component just prior to application to thesurface, with or without a catalyst. The prepolymer is formed from thereaction of excess isocyanate with the polyol/polyamine component.

In one aspect of the subject matter disclosed herein, a compositioncomprising a mixture of two or more individual putty compositions isprovided, wherein a first putty composition comprises one or morereactive components and one or more additive (filler) components and asecond putty composition comprises one or more reactive components andone or more additive (filler) components.

In some embodiments, the one or more reactive components in the firstputty composition comprise an isocyanate and/or mixtures of isocyanates.In some embodiments, the isocyanate is[5-[2-[2-(4-isocyanatobenzoyl)oxypropanoyloxy]-ethoxy]-1-methyl-2-oxo-pentyl]-4-isocyanatobenzoate(ALD).

In some embodiments, the second putty comprises one or more polyols,hydroxyl terminated polymers of glycolide, lactide, p-dioxanone,trimethylene carbonate and/or caprolactone, polyethylene glycol, acopolymer of ethylene oxide and propylene oxide (poloxamers),1,2-ethanediol (ethylene glycol), 1,2-propanediol (propylene glycol),1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,3-cyclopentanediol,1,6-hexanediol, 1,4-cyclohexanediol, 1,8-octanediol, glycerol,polyethylene glycol and polypropylene glycol with molecular weights of400-10000, and combinations thereof.

The one or more additive components in each individual reactive puttycomposition may comprise a carbonate or bicarbonate selected fromcalcium carbonate, magnesium carbonate, aluminum carbonate, ironcarbonate, zinc carbonate, calcium bicarbonate, sodium bicarbonate,embedded particles of bone, demineralized bone, bone morphogeneticprotein, hydroxyapatite, calcium phosphate, silicated calcium phosphate,absorbable phosphate glass, an inorganic material, a bone substitutematerial, a carbonate selected from magnesium carbonate, aluminumcarbonate, iron carbonate, zinc carbonate, calcium carbonate, sodiumcarbonate, and a bicarbonate of magnesium, aluminum, iron, or zinc, andcombinations thereof.

In some embodiments, the one or more reactive components in the secondputty composition comprises polyurethane formed from one or more polyolsreacted with isocyanate, which may be[5-[2-[2-(4-isocyanatobenzoyl)oxypropanoyloxy]-ethoxy]-1-methyl-2-oxo-pentyl]-4-isocyanatobenzoate(ALD).

In some embodiments, the one or more polyols comprise hydroxylterminated polymers of glycolide, lactide, p-dioxanone, trimethylenecarbonate and/or caprolactone, polyethylene glycol, a copolymer ofethylene oxide and propylene oxide (poloxamers), 1,2-ethanediol(ethylene glycol), diethylene glycol, 1,2-propanediol (propyleneglycol), 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol,1,3-cyclopentanediol, 1,6-hexanediol, 1,4-cyclohexanediol,1,8-octanediol, glycerol, polyethylene glycol and polypropylene glycolwith molecular weights of 400-10000, and combinations thereof.

In certain embodiments, the compositions disclosed herein may furthercomprise a third, a fourth, a fifth (or more) putty compositions, and/oradditional putty additives.

In other aspects, a sterilized composition comprising a mixture of twoor more individual putty compositions is provided, as further describedherein.

In some embodiments, the composition is either fully absorbable orpartially absorbable. In other embodiments, the composition is notabsorbable.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides curable, absorbable polyurethane andpolyureaurethane compositions. The compositions are most often formed bycombining an isocyanate or an isocyanate prepolymer of the inventionwith a polyol and/or a polyamine as described herein to form apolyurethane and/or polyurea-based polymer. In certain embodiments, theisocyanate and polyol are further combined with one or more chainextenders as described below. The combination results in apolymerization reaction that produces heat, but is generally less than60° C. and no noxious fumes are released during or after mixing.

The compositions of the invention are biocompatible, fully or partiallybiodegradable are suitable for use in vivo, particularly in bone repairand replacement surgery, and especially for use as a bone cement, a bonesubstitute and/or a bone hemostatic agent. As used throughout thepresent specification, the term “biocompatible” refers to materials thatdo not induce undesirable side effects when administered or implanted invivo. A biocompatible material may also be described herein as“nontoxic”. As used throughout the present specification, the terms“degradable”, “biodegradable”, “resorbable”, and “absorbable” are usedinterchangeably to refer to the ability of the claimed compositions todegrade (partially or completely) under physiological conditions intonon-toxic products that can be metabolized or excreted within a periodof time, generally several weeks up to a year or about 18 to 24 monthsor longer.

The polyurethane compositions of the invention are polymers orprepolymers formed from the reaction of (i) a degradable polyaromaticisocyanate, preferably a diisocyanate or a polyisocyanate, and (ii) apolyol and/or a polyamine, which may or may not be degradable, with theoptional addition of (iii) a chain extender or curative, which may ormay not be degradable. As used throughout the present specification, theterms “isocyanate” and “polyisocyanate” may be used interchangeably torefer to the polyaromatic isocyanates used in making the curable,absorbable polyurethanes of the invention. The term “polyisocyanate”encompasses a chemical structure having two or more isocyanate groups.The term “polyaromatic” refers to isocyanate groups residing on two ormore aromatic rings. The term “polyol” encompasses a chemical structurehaving two or more hydroxyl groups. As used herein, the term “polyol”refers to both diols and polyols.

The polyaromatic isocyanates used to form the polyurethane compositionsof the invention comprise at least one hydrolysable linkage bridging thearomatic rings. In certain embodiments, the hydrolysable linkagebridging the aromatic rings is derived from glycolic acid, lactic acid,caprolactone, or p-dioxanone. Suitable polyaromatic isocyantes aredescribed in more detail below. The term “polyaromatic isocyanates” asused herein is meant to distinguish from aromatic isocyantes having onlya single aromatic ring such as toluene diisocyante. The isocyanate,polyol, and chain extender components of the compositions of theinvention, as well as other optional components, are described in moredetail below.

The compositions of the invention are most often low-exotherm,biocompatible compositions suitable for use in vivo at least in thattheir formation does not produce toxic fumes or tissue-damaging amountsof heat and their degradation under physiological conditions does notproduce toxic by-products and/or is not toxic to the implant recipient.In a preferred embodiment, the maximum exotherm of the polymerizationreaction is 65° C. or less, and most preferably 50° C. or less.

In certain embodiments, the compositions are osteopromotive. As usedthroughout the present specification, the term “osteopromotive”encompasses the ability to support, enhance or accelerate the growth ofnew bone tissue by one or more of osteogenesis, osteoconduction, and/orosteoinduction. In certain embodiments, the compositions are alsohemostatic. A hemostatic composition of the invention is able to beapplied to to the surface of bleeding bone in its uncured state, andstop the bleeding within a period of time. For example, the bleeding isstopped immediately after application of the composition or within about1 minute, or within about 2-5 minutes, or within about 5-10 minutes. Inpreferred embodiments the hemostatic compositions are adhesive andcapable of adhering to bone and/or soft tissue. Although the hemostasisis primarily mechanical (tamponade), in certain embodiments a hemostaticcomposition of the invention may also contain one or more agents thatact as active chemical hemostats. Non-limiting examples include, bloodclot-inducing agents such as prothrombin, thrombin, oxidized cellulose,microcrystalline collagen, fibrinogen, and fibrin. In one embodiment,the composition may also comprise one or more of epinephrine, tannicacid, ferrous sulfate, and the double-sulfates of a trivalent metal anda univalent metal such as potassium aluminum sulfate and ammoniumaluminum sulfate. Thus, a composition of the invention in either itsfluid, putty or solid form is also preferably hemostatic, mechanicallyor chemically, or by a combination of mechanical and chemicalhemostasis. The term “fluid form” refers to the uncured form of thecomposition which is a viscous liquid or putty or which hardens or“cures” into the solid form.

The instant invention further provides self-setting (i.e., increasedviscosity or hardening after mixing) compositions for medical use thatare produced by mixing, kneading or combining together two or moreindividual putties. The individual component putties can be provided insterile form, and may be hand mixed at the surgical table prior toimplantation. Once mixed, the compositions disclosed herein are capableof hardening in the body and are particularly useful for orthopedicapplication as a bone hemostat, a bone adhesive, a bone void filler, ora bone cement. The compositions also can be used as soft tissue bulkingagents, soft tissue hemostats, inhibitors of surgical adhesionformation, and as delivery vehicles for drugs and therapeutic agents.

The term “bone cement” is meant to distinguish certain embodiments ofthe invention from other embodiments, such as soft tissue adhesives,which may not possess mechanical properties suitable for use in bonerepair. A bone cement composition of the invention when fully cured hasa compressive strength, tensile strength, and elasticity suitable foruse in bone repair or reconstruction. The solid form also bonds to boneor metal surfaces and reaches a self-supporting bond strength withinabout 90 minutes. In one embodiment, a fully cured composition of theinvention has a compressive strength of from 30 to 150 MPa, or greater,a tensile strength of from 20 to 80 MPa, or greater, and an elasticitydefined by a Modulus of Elasticity of from 1,400 to 1,800 MPa, orgreater. In certain embodiments the compressive strength is at least 30MPa, at least 40 MPa, at least 50 MPa, at least 60 MPa, at least 70 MPa,at least 80 MPa, or at least 100 MPa. In some embodiments, thecompressive strength is greater than 100 MPa or greater than 150 MPa. Inone embodiment, the compressive strength is between 100 and 150 MPa orbetween 150 and 200 MPa. Preferably, the solid form is sufficientlydurable to be drillable or machineable. In certain embodiments the solidform has a tensile strength of at least 20 MPa, at least 30 MPa, atleast 40 MPa, at least 50 MPa, at least 60 MPa, or at least 80 MPa. Incertain embodiments the solid form has a Modulus of Elasticity of atleast 1,400 MPa, at least 1,500 MPa, at least 1,600 MPa, or at least1800 MPa. In one embodiment, the solid form has a compressive strengthof at least 60 or 70 MPa, a tensile strength of at least 40 or 50 MPa,and an elasticity of at least 1,600 or 1,800 MPa. The mechanicalproperties described here refer to the properties of the polyurethanealone, without the addition of other, optional, materials which mayfurther increase these physical properties, especially compressivestrength. In one embodiment, the polyurethane compositions of theinvention do not comprise an optional particulate material. In certainembodiments, the particulate material, if present, is present in anamount up to about 80% by weight of the composition.

The fully cured form of a composition of the invention is also referredto herein as the solid form of the composition. This is to distinguishfrom the fluid form which may be a putty and/or viscous liquid thathardens or “cures” into the solid form. In addition, in preferredembodiments the solid form bonds to bone or metal surfaces and reaches aself-supporting bond strength within about 90 minutes. The solid formfurther bonds with tensile and shear strength equal to normal bonewithin about 72 hours. A composition of the present invention hardensinto its solid form at room temperature or at body temperature withinabout 5 to 90 minutes. In certain embodiments the composition hardensinto its solid form in about 10, 20, 30, 40, 50, 60, 70, 80, or 90minutes.

The fluid form of the compositions is a putty or viscous liquid whichhardens or “cures” into the solid form. The fluid form is moldable orpliable and does not adhere appreciably to surgical gloves orinstruments but adheres well to moist bone surfaces. The fluid form ofthe composition is also resistant to dislodgement by surgical irrigationat the application site. The fluid form is useful, for example, to filla cavity in the bone, for injection through a syringe to the site ofapplication, or for bone reconstruction. The fluid form of thecompositions of the invention remains in a moldable state at roomtemperature for up to 120 minutes. In one embodiment, the compositionremains in a moldable state for 10, 15, 20, 30, 40, 60, 80, 90, or 120minutes. The rate of cure can be increased, for example, by the additionof a catalyst as described in more detail below. In addition, thearomatic isocyanate monomers described herein will react fastest withthe polyamine component, then the polyol component and slowest withwater. In addition, the rate of cure can be decreased, for example, byreplacing one or more primary diols in the composition with secondarydiols.

During the curing of a polyurethane formed from liquid components, thecomposition may undergo a transition to a “taffy” like state prior tofully setting. Such a “taffy” phase which may also be considered“putty-like” is distinguished from the component putties describedherein. The component putties comprise particulate “fillers” toestablish their “putty-like” characteristics.

The compositions of the invention are fully or partially degradableunder physiological conditions within a period of time. Where thecompositions are fully degradable, they are degraded within about 12months. The degradation may be enzymatic or non-enzymatic or acombination of both. In one embodiment, the compositions of theinvention are initially degradable into non-toxic products by anon-enzymatic hydrolysis under physiological conditions. In a preferredembodiment, the compositions are fully degradable within a period oftime less than 12-24 months. In certain embodiments, the degradationtime does not exceed 3 months or 6 months. In one embodiment, acomposition of the invention is degradable within about 2 to 4 weeksafter placement in vivo. In other embodiments, a composition of theinvention is fully degradable within about 4 to 6 weeks, or within about2 to 4 months, 4 to 6 months, 6 to 8 months, or 8 to 12 months. Incertain embodiments, the compositions comprise components that are fullydegradable or absorbable. In other embodiments, the compositions arecomprised of components that are partially degradable or absorbable, ornon-degradable. In certain embodiments, the compositions are formed froma combination of fully degradable, partially degradable, andnon-degradable components.

The hydrolysable embodiments of the invention are degradable at leastdue to the presence of functional groups in the polymer chain that arereadily hydrolysable under physiological conditions. Thus, the term“partially degradable” as used in the present specification encompassesthe percentage of functional groups in the polymer chain that arehydrolyzed compared to the total number of hydrolysable groups. In thiscontext, a partially degradable polyurethane of the inventionencompasses compositions in which, after a suitable period of time,about 75% of the hydrolysable groups are hydrolyzed. In certainembodiments, a partially degradable compositions is one in which about25% to 75% or 50% to 75% or about 75% to 90% of the hydrolysable groupsare hydrolyzed. The rate of degradation of the polyurethane compositionsof the invention can be controlled in order to provide compositions thatdegrade at a slower or faster rate, compared to a base composition. Ingeneral, the rate of degradation is controlled by varying the isocyanateand polyol/polyamine components of the compositions, as well as theoptional chain extender component according to the following parameters.In one aspect, the rate of degradation is controlled by choice of theisocyanate. Generally, the more glycolide in the hydrolysable bridge,the faster it will degrade while more lactide in the hydrolysable bridgewill degrade slower, and combinations of glycolide and lactide willdegrade at intermediate rates. In another aspect, the rate ofdegradation is controlled by varying the hydrophobic/hydrophilic balanceof the polyol/polyamine component. Generally, the more carbon atoms ormethylene groups between the hydrolysable functions, the slower will bethe hydrolysis. For example, ethylene glycol will provide a compositionthat hydrolyses more rapidly than, for example, propane diol, which inturn hydrolyses more rapidly than butane diol. In addition, the use ofhydrolysable diamines as chain extenders will increase the rate ofhydrolysis. In another aspect, copolymers of caprolactone and glycolidehydrolyze faster than copolymers of caprolactone and lactide and theaddition of D,L-lactide also increases the rate of hydrolysis. Thus, forexample, a bis-diphenyldiisocyanate bridged with a polyglycolide, apolyglycolide-co-lactide, a polylactide, apolycaprolactone-co-glycolide, a polycaprolactone-co-lactide, apolycaprolactone will hydrolyze at increasingly slower rates. Forcomparison, polyurethanes prepared using methylenebis-diphenyldiisocyanate, with no hydrolyzable linkages, are notsignificantly degradable under physiological conditions. In otherembodiments, enzymatic sensitive sites such as di or polylysines orarginines are incorporated into one or more of the substituents.

In certain embodiments, the fully cured compositions of the inventionhave a certain defined pore size. Porosity is controlled through theinclusion of water, surfactants, and/or cell openers during the processof combining the one or more isocyanate components with thepolyol/polyamine component to form the polyurethane compositions of theinvention. For example, porosity may be controlled by the addition of asmall amount of water to a prepolymer containing isocyanate groups. Thewater reacts with the isocyanate group to form carbon dioxide resultingin porosity. In one embodiment, the solid form has an average pore sizein the range of from about 5 to 700 microns. In certain embodiments, theaverage pore size is from about 5 to 100 microns, from about 5 to 300microns, from about 5 to 500 microns, and from about 5 to 700 microns.In certain embodiments, the average pore size is from about 100 to 300microns, from about 200 to 500 microns, from about 300 to 600 microns,and from about 500 to 700 microns, or greater. In another embodiment,the solid form has an average pore size in the submicron range. Incertain embodiments, the average pore size is from about 100 to 1000nanometers, from about 100 to 400 nanometers, from about 400 to 800nanometers, from about 200 to 600 nanometers, or from about 500 to 900nanometers. Porosity may also be introduced into the cured polyurethanesthrough the use of porous filler materials (eg commercially availablecalcium phosphates with pore sizes of 200 microns or greater). Thisapproach is particularly useful in the multi-putty embodiments.

The compositions of the invention are provided either in a fluid form orin the form of a binary composition of (1) one or more of theisocyanates of the invention and (2) at least one polyol. A chainextender may also be used, as described below. The binary compositionmay also comprise, e.g., a prepolymer and a chain extender. A prepolymeris a low molecular weight polymer having reactive end groups, e.g.,hydroxyl groups. As used in this context, a low molecular polymer refersto a polymer having a number average molecular weight in the range ofabout 500 to 20,000 or 500 to 10,000. The prepolymer is formed, forexample, from the initial reaction of the one or more isocyanates withthe at least one polyol. Formation of a high molecular weight polymer isachieved by addition of the chain extender.

The compositions of the invention may also be provided as a package orarticle of manufacture containing a fluid form (which can, for example,be frozen to halt the curing process). In another embodiment, thecompositions are provided as a binary package or article of manufacturecontaining in a first package a prepolymer of the isocyanate and thepolyol/polyamine components and in the second package one or more chainextenders. The second package may also optionally contain a crosslinker.In another embodiment, the compositions are provided as a binary packageor article of manufacture containing in a first package one or morepolyaromatic di- or polyisocyanates as described herein and in a secondpackage one or more of the polyol/polyamine components as describedherein. A third package may optionally contain a chain extender orcrosslinker. Generally, the amount of polyisocyanate (I) present in thefirst package is in excess of the amount of polyol and/or polyamine (H)in the second package. The amount of isocyanate (I) is the molar ratioof NCO groups to active hydrogen functional groups (H) (e.g., hydroxyl,amino, and mixtures thereof). Generally, the ratio of polyisocyanate topolyol/polyamine (I:H) is at least 2:1. In certain embodiments, thepackages contain relative amounts of the isocyanate todiol/polyol/polyamine (I:H) of about 1.5:1, about 2:1, about 3:1, orabout 4:1. In other embodiments, the ratio is about 5:1, about 8:1,about 10:1, about 20:1, or about 50:1. In certain embodiments, a packageor article of manufacture of the invention has a shelf life of at least1-2 years. In certain embodiments, the package has a shelf life of 6months, 12 months, 18 months, or 24 months. In certain embodiments thepackage is sterile or sterilizable, for example by irradiation or byautoclaving. In certain embodiments, the package further comprises asyringe.

As discussed above, some embodiments of the invention are bone cementsor hemostatic agents and, as such, are required to have differentmechanical properties compared to, e.g., soft tissue adhesives orhemostats. The compositions of the invention are intended to cure insitu, most often to bond to the surrounding bone. The cements of theinvention will also bond, for example, to a metal plate or othersurgically introduced article, if present. In contrast, pre-polymerizedbone fillers are fully polymerized before placement into the body andare therefore incapable of bonding. Organic polymeric bone fillers arealso generally porous composite materials containing, for example, apolymer matrix having a relatively high weight percent of particlesembedded in the matrix. The particles serve to increase the compressivestrength of the polymer and may also promote the growth of new bone(e.g., osteoblasts) into the matrix. The compositions of the inventionmay contain particulate materials, as described below, but generallysuch materials, if present, will be present in an amount of up to about80% by weight of the composition. This is because such materials are notemployed in the present compositions to increase the mechanical strengthof the composition but instead for other purposes, such as, for example,to promote the growth of bone into the site. Thus, in some embodiments,the compositions of the invention further comprise an optionalparticulate material. In one embodiment, the particulate material is acarbonate, e.g., calcium carbonate, magnesium carbonate, aluminumcarbonate, iron carbonate, zinc carbonate, calcium bicarbonate, andsodium bicarbonate. In other embodiments, the particulate material is aceramic such as substituted or augmented calcium phosphate (e.g,silicate, strontium or magnesium substitution) or a glass such asbioglass. In some embodiments, the particulate material is one or moreof calcium sulfate, calcium phosphosilicate, sodium phosphate, calciumaluminate, calcium phosphate, hydroxyapatite, demineralized bone, ormineralized bone. Preferably, if included in the compositions of theinvention, such particulate materials (including e.g., carbonates,ceramics, glasses, etc.) form up to about 80% by weight of the fullycured composition.

Optionally, the process may also comprise the inclusion of a surfactant,at least one radiopaque substance, or at least one protein, or anycombination of the foregoing.

The process may further comprise the inclusion of one or morecross-linkers. In one embodiment, the one or more cross-linkers isselected from glycerol and pentaerythritol. In one embodiment, thecross-linker is a trifunctional castor-oil based polyol.

In certain embodiments, the process further comprises the inclusion ofone or more of bone, demineralized bone matrix, bone morphogeneticprotein, calcium phosphate, siliconized calcium phosphate, calciumpyrophosphate, hydroxyapatite, poly methyl methacrylate, glass-ionomer,absorbable phosphate glass, calcium sulfate, or tricalcium phosphate,bone-like mineral (e.g., crystalline hydroxyapatite or calciumpyrophosphate).

In one embodiment, the compositions of the invention are formed by aprocess of combining an isocyanate prepolymer with a polyol orchain-extender, and a catalyst, optionally with one or more particulatematerials as described above, to form a poly(urethane-isocyanurate)composition. In another embodiment, the isocyanate prepolymer iscombined with a polyol, water, and a catalyst, optionally with anosteoconductive filler, to form a poly(urethane-urea-isocyanurate)composition.

In one embodiment, the curable, absorbable polyurethane compositions ofthe invention comprise a glycolide-linked polyaromatic diisocyanate anda polycaprolactone-co-glycolide polyol. It should be understood that thecompositions of the invention are formed from the reaction of apolyaromatic polyisocyanate, one or more polyols and/or polyamines and,optionally, a polyol and/or a polyamine as a chain extender. Thus, inthis context, and as used throughout the present disclosure with respectto the compositions of the invention, the term “comprises” refers to thepolyurethane or polyureaurethane reaction product of an isocyanate, apolyol/polyamine and, optionally, a polyol and/or a polyamine as a chainextender. In one embodiment, the composition further comprisesbutanediol, e.g., as a chain extender. In one embodiment, thecomposition further comprises one or more of water, a carboxylic acid,e.g., benzoic acid (as a foaming agent), a divalent or polyvalent metalsalt, a metal carbonate or bicarbonate, or a phosphate, e.g., forosteoconductivity. In one embodiment, the glycolide-linked diisocyanatemonomer has the following structure:

In one embodiment, the polycaprolactone-co-glycolide polyol has thefollowing structure:HOCH₂CO₂CH₂CH₂CH₂CH₂CO₂CH₂OH

In one embodiment, the curable, absorbable polyurethane compositions ofthe invention comprise a lactide linked diisocyanate and apolycaprolactone-co-lactide polyol. In one embodiment, the compositionfurther comprises butanediol, e.g., as a chain extender. In oneembodiment, the composition further comprises one or more of water, acarboxylic acid, e.g., benzoic acid (as a foaming agent), a divalent orpolyvalent metal salt, a metal carbonate or bicarbonate, or a phosphate,e.g., for osteoconductivity. In one embodiment, the lactide-linkeddiisocyanate monomer has the following structure:

In one embodiment, the polycaprolactone-co-lactide polyol has thefollowing structure:HOCH(CH₃)CO₂CH₂CH₂CH₂CH₂CO₂CH(CH₃)OH

In one embodiment, the curable, absorbable polyurethane compositions ofthe invention comprise a tetraisocyanate. In one embodiment, thetetraisocyanate is a caprolactone ethylene glycol linked phenylalaninediisocyanate. This may be reacted with the tetra-amine precursor of thetetraisocyanate described above. In one embodiment, the compositionfurther comprises one or more of water, a carboxylic acid, e.g., benzoicacid (as a foaming agent), a divalent or polyvalent metal salt, a metalcarbonate or bicarbonate, or a phosphate, e.g., for osteoconductivity.

The Isocyanate Component

The absorbable polyurethane compositions of the invention are preparedfrom one or more polyaromatic di- or polyisocyanates having at least onehydrolysable linkage bridging at least two of the aromatic rings. Incertain embodiments, the hydrolysable linkage bridging the aromaticrings is derived from glycolic acid, lactic acid, caprolactone, orp-dioxanone. In most cases, the hydrolyzable linkage is an ester whichmay degrade into an acid and an alcohol as a result of exposure to wateror to naturally occurring esterases. Amide linkages are usually moredifficult to hydrolyze than esters. Another option is the easilyhydrolyzable acid anhydride linkage. Sulfonamides may also be consideredin this context. The polyaromatic di- or polyisocyanates describedherein are distinct from isocyantes having only a single aromatic ringsuch as toluene diisocyante, methylene bis-p-phenyl diisocyanate, andaromatic polyisocyanates generally.

Suitable isocyanates for use in making the compositions of the inventionare described in U.S. Pat. No. 7,772,352 and U.S. Patent ApplicationSerial No. 2009/0292029, each of which is incorporated herein byreference.

In certain embodiments, an absorbable polyurethane composition of theinvention is prepared from one or more aromatic isocyanates selectedfrom the following formulas I, II, III, IV, and V:

whereineach X represents a member independently selected from:CH₂COO—(glycolic acid moiety),CH(CH₃)COO—(lactic acid moiety),CH₂CH₂OCH₂COO—(dioxanone moiety),CH₂CH₂CH₂CH₂CH₂COO—(caprolactone moiety),(CH₂)_(y)COO—where y is one of the numbers 2, 3, 4 or 6-24 inclusive,and(CH₂CH₂O)_(z′)CH₂COO—where z′ is an integer between 2 and 24, inclusive;each X′ represents a member independently selected from:OOCH₂—(glycolic ester moiety),OOC(CH₃)CH—(lactic ester moiety),OOCCH₂OCH₂CH₂—(dioxanone ester moiety),OOCH₂CH₂CH₂CH₂CH₂—(caprolactone ester moiety),OOC(CH₂)_(y)—where y is one of the numbers 2, 3, 4 or 6-24 inclusive,andOOCCH₂(OCH₂CH₂)_(z′)—where z′ is an integer between 2 and 24, inclusive;each X″ represents a member independently selected from:OCH₂CO—(glycolic acid moiety),OCH(CH₃)CO—(lactic acid moiety),OCH₂CH₂OCH₂CO—(dioxanone moiety),OCH₂CH₂CH₂CH₂CH₂CO—(caprolactone moiety),O(CH₂)_(y)CO—where y is one of the numbers 2, 3, 4 or 6-24 inclusive,andO(CH₂CH₂O)_(z′)CH₂CO—where z′ is an integer between 2 and 24, inclusive;each Y represents a member independently selected from:COCH₂O—(glycolic ester moiety),COCH(CH₃)O—(lactic ester moiety),COCCH₂OCH₂CH₂O—(dioxanone ester moiety),COCH₂CH₂CH₂CH₂CH₂O—(caprolactone ester moiety),CO(CH₂)_(m)O—where m is an integer between 2-4 or 6-24 inclusive, andCOCH₂O(CH₂CH₂O)_(n)—where n is an integer between 2 and 24, inclusive;each Y′ represents a member independently selected from:OCH₂OC—(glycolic ester moiety),O(CH₃)CHOC—(lactic ester moiety),OCH₂CH₂OCH₂OC—(dioxanone ester moiety),OCH₂CH₂CH₂CH₂CH₂OC—(caprolactone ester moiety),O(CH₂)_(m)OC—where m is an integer between 2-4 or 6-24 inclusive, and(OCH₂CH₂)_(n)OCH₂OC—where n is an integer between 2 and 24, inclusive;each R is a benzyl or an alkyl group, the alkyl group being eitherstraight-chained or branched;each p is independently an integer between 1 and 4, inclusive;Z is O or NH; andRn represents one or more members selected from H, alkoxy, benzyloxy,aldehyde, halogen, carboxylic acid and —NO₂, which is attached directlyto an aromatic ring or attached through an aliphatic chain. The aromaticcompound is selected from amine and/or carboxylic acid containingphenols, such as amino-phenols, amino-salicylic acids and amino-benzoicacids.

In other embodiments, an absorbable polyurethane composition of theinvention is prepared from one or more aromatic isocyanates selectedfrom the following formula VI:

wherein:R is alkylene-[C(R⁴)(R⁵)]₅-alkylene-, wherein (1) one or more of the—CH₂— moieties in one or more alkylene chain portions of R areoptionally replaced by O or S; or (2) one or more of the —CH₂CH₂—moieties in the alkylene chain portions of R are optionally replaced by—C(═O)O or OC(═O);each R¹ is independently [C(R²)(R³)]_(p)Z;each Z is independently alkoxy, aralkyloxy, C(═O)H, halogen, C(═O)OH, orNO₂;each R² and R³ is independently H or alkyl;R⁴ is H, OR⁶ or CH₂OR;R⁵ is H or CH₂OR;each R⁶ is independently:

each X is independently CH(CH₃)C(═O)O, (CH₂)_(y), C(═O)O, or(CH₂CH₂O)_(z)CH₂C(═O)O;each X is independently OC(═O)CHCH₃, OC(═O)(CH₂)_(y) orOC(═O)CH₂(OCH₂CH₂)_(z);each a and b is independently an integer from 1 to 6;n is an integer from 0 to 4;p is an integer from 0 to 10;s is the integer 0 or 1; andeach y and z is independently an integer from 1 to 24.

In a particular embodiment, an absorbable polyurethane composition ofthe invention is prepared from one or more aromatic isocyanates selectedfrom the following compounds, 1-12:

The Isocyanate Component of the Multi-Putty Embodiment

Any of the di- or polyisocyanates discussed above are preferred for themulti-putty embodiments. In certain embodiments, the isocyanate is anaromatic isocyanate, an aliphatic isocyanate, a cycloaliphaticisocyanate, or an adduct of an isocyanate. Examples of suitable adductsof isocyanate include a hexamethylene diisocyanate trimer (DESMODURN-3390) and a hexamethylene diisocyanate biuret (DESMODUR N-100) bothcommercially available from Bayer AG. An example of a suitable aromaticisocyanate is diphenylmethanediisocyanate, also known as “MDI.”Commercially available examples of diphenylmethanediisocyanate includemixtures of 2,4-diphenylmethane diisocyanate and4,4-diphenylmethanediisocyanate isomers (ISONATE 50 OP, Dow Chemical Co.and RUBINATE 9433, Huntsman Corp.). Diphenylmethanediisocyanate is alsocommercially available in its pure 4,4-diphenylmethanediisocyanate form(MONDUR M, Bayer AG and RUBINATE 44, Huntsman Corp.). Other examples ofsuitable aromatic isocyanates include the commercially availablepolymeric isocyanates ISONATE 143L, ISONATE PAPI 901, and ISONATE PAPI27 (Dow Chemical Co.). These diisocyanates, particularly thediphenylmethane derivatives, generally result in non-absorbable orslowly absorbable polyurethanes. A preferred isocyanate is[5-[2-[2-(4-Isocyanatobenzoyl)oxypropanoyloxy]-ethoxy]-1-methyl-2-oxo-pentyl]-4-isocyanatobenzoate,or “ALD”, which is readily hydrolysable.

The Polyol/Polyamine Component

The diols, polyols, and polyamines suitable for use in forming thepolyurethane and polyureaurethane compositions of the invention areeither degradable or non-degradable, or a mixture of the two. As usedherein, the term “polyol” is meant to refer generically to diols andpolyols, unless indicated otherwise. Generally, the compositions of theinvention are formed by the combination of an excess of the isocyantecomponent with the polyol/polyamine component. The relative amounts arecalculated as the molar ratio of NCO groups of the isocyanate component(I) to the active hydrogen functional groups (H) (e.g., hydroxyl, amino,and mixtures thereof) of the polyol/polyamine component. Generally, theratio of polyisocyanate to polyol/polyamine (I:H) is at least 2:1. Incertain embodiments, the ratio is about 1.5:1, about 2:1, about 3:1, orabout 4:1. In other embodiments, the ratio is about 5:1, about 8:1,about 10:1, about 20:1, or about 50:1.

In certain embodiments, the polyol/polyamine component is present in anisocyanate prepolymer in an amount of from about 5% to about 50% byweight of the prepolymer. In certain embodiments, the polyol/polyaminecomponent is present in an amount of from about 5% to 10%, from about10% to 20%, from about 20% to 35%, from about 25% to 40%, or from about35% to 50% by weight of the prepolymer.

Polyols suitable for use in the present invention include biocompatiblenaturally occurring polyols, synthetic polyols, and mixtures thereof. Incertain embodiments, the polyols comprise at least one ester group. Incertain embodiments, the polyol comprises 2 to 4 ester groups or 5 to 10ester groups. Preferably, the polyol has two or more hydroxyl groups.Suitable polyols include diols and polydiols having repeating unitscontaining up to about 18 carbon atoms. Examples of suitable diolsinclude 1,2-ethanediol (ethylene glycol), 1,2-propanediol (propyleneglycol), 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol,1,3-cyclopentanediol, 1,6-hexanediol, 1,8-octanediol and combinationsthereof. Examples of preferred polydiols include polyethylene glycolwith molecular weights of from about 500 to about 10000,polytetramethylene ether glycols, polyols derived from glycolide,lactide, trimethylenecarbonate, p-dioxanone and/or caprolactone withmolecular weights of about 500 to about 10000.

In one embodiment, the polyol is a synthetic polyol selected from apolycaprolactone polyol, polyester polyols, polyadipate polyols (e.g.,poly(hexane-adipate)diol, poly(butane-adipate)diol,poly(ethylene/propylene-adipate)diol, poly(hexane/adipate/isophthalatediol)), and polyols that have been derived from a synthetic acid (e.g.,isophthalic acid, maleic acid). An example of a suitable biocompatiblesynthetic polyol is a polycaprolactone diol that is commerciallyavailable from Dow Chemical under the trade name TONE 32 B8. apolycaprolactone co-glycolide or a polycaprolactone co-lactide. Furthernon-limiting examples of suitable synthetic polyols includepoly(oxypropylene)glycols, poly(oxytetramethylene)glycols, andpoly(oxyethylene)glycols. In one embodiment, the synthetic polyol isselected from a polycaprolactone co-glycolide or a polycaprolactoneco-lactide.

In one embodiment, the polyol is a naturally occurring polyol selectedfrom castor oil, safflower oil, lesquerella oil, the polyols that may beobtained by chemical modification of naturally occurring vegetable oils(e.g., castor oil, olive oil, sesame oil, corn oil), naturally occurringoils that have been trans-esterified (e.g., a modified castor oil polyolthat has been prepared by the transesterification reaction of naturalcastor oil with suitable crosslinkers (e.g., glycerol,trimethylolpropane, and the like) or with acids such as adipic acid),and naturally occurring oils that have been hydrogenated. Furthernon-limiting examples of suitable naturally occurring polyols includethe commercially available castor-oil-based polyols CASPOL5001,CASPOL1962, and CASPOL5004 (all available from CasChem, Inc.). Incertain embodiments, the polyol is not a naturally occurring polyol suchas castor oil, safflower oil, lesquerella oil.

In certain embodiments, an isocyanate prepolymer is combined with apolyamine to form a poly(urethane-urea). The polyamine may be a primaryor secondary di-amine, or a hindered amine. Non-limiting examples ofsuitable polyamines include, hindered diamine (e.g., isophorone diamine,“IPDA”), 1,4-cyclohexyl diamine, 1,3-pentane diamine, and aliphaticsecondary diamines, and mixtures thereof. In certain embodiments of thepresent invention, aliphatic diamines and cycloaliphatic diamines may beparticularly suitable, and may offer improved biocompatibility.Commercially available examples of suitable polyamines include CLEARLINK1000 (Dorf Ketal).

Amines including diamines that may be suitable for use in thepreparation of polyurea and polyureaurethanes include but are notlimited to polyethyleneimines, PEG amines with weight average molecularweights from about 500 to about 5,000, polyoxypropylenediaminesavailable under the tradename JEFFAMINES (Huntsman Corporation, Houston,Tex.), spermine, spermidine, hexamethylenediamine, octamethylenediamine,decamethylenediamine, dodecamethylenediamine, hexadecamethylenediamine,octadecamethylenediamine, polyamidoamine dendrimers, dextrans,PEG-dextran conjugates, cysteines, proteins containing amines,non-biologically active symmetrical and unsymmetrical diamino compoundscontaining saturated and unsaturated, substituted and unsubstitutedalkyl, aryl and alkylaryl groups having from about 2 to about 18 carbonatoms and hydrolysable diamines having the following formulas:

The Polyol/Polyamine Component for the Multi-Putty Embodiment

Polyols suitable for use in the multi-putties disclosed herein includeany of the biocompatible naturally occurring polyols, synthetic polyols,and mixtures thereof disclosed herein. In certain embodiments, thepolyols comprise at least one ester group. In certain embodiments, thepolyol comprises 2 to 4 ester groups or 5 to 10 ester groups. Suitablepolyols have at least two hydroxyl groups. In certain embodiments, thepolyol has three or more hydroxyl groups.

The Chain-Extender/Crosslinker Component

In certain embodiments, one or more optional chain extenders orcrosslinkers is incorporated in the formation of the compositions of theinvention. In certain embodiments, only a chain extender is present. Inother embodiments, both a chain extender and a crosslinker is present.In one embodiment, the one or more chain extenders is a low molecularweight hydroxyl- and/or amine-terminated compound having a molecularweight in the range of 10 to 500 Daltons and a functionality of at leasttwo. In one embodiment, the one or more chain extenders has afunctionality of one or two. In certain embodiments, the chain extenderis a short-chain diol or diamine. In a particular embodiment, the chainextender is selected from glycerol, 1,4 butanediol, 1,6-hexanediol,diethylene glycol, and combinations thereof. Chain extenders having afunctionality of three or more than three are also referred to ascrosslinkers. In certain embodiments, the compositions of the inventionare formed without crosslinkers and the compositions of the inventionare not crosslinked. In other embodiments, the compositions of theinvention are formed with one or more crosslinkers. The degree ofcrosslinking can be controlled, for example, by varying the amount ofcrosslinker present.

In certain embodiments, the chain-extender or crosslinker is present inan isocyanate prepolymer in an amount in the range of about 5% to about80% by weight of the isocyanate prepolymer. In certain embodiments, thechain-extender or crosslinker is present in an amount of from about 5%to 20%, about 20% to 30%, about 30% to 40%, about 40% to 50%, about 50%to 60%, from about 60% to 70%, or from about 70% to 80% by weight of theisocyanate prepolymer.

The chain extender for use in accordance with the invention may bedegradable or non-degradable. Preferably, at least one degradable chainextender is used. Suitable degradable chain extenders for use in thepresent invention are described in U.S. Patent Application Serial No.2009/0082540, which is incorporated herein by reference. In oneembodiment, the at least one degradable chain extender isHOCH₂CO₂CH₂CH₂OH or HOCH₂CO₂CH₂CH₂O₂CCH₂OH.

Other suitable chain-extenders or crosslinkers include a natural orsynthetic aliphatic polyols. Suitable polydiols for use in the presentinvention include diol or diol repeating units with up to 8 carbonatoms. Non-limiting examples include 1,2-ethanediol (ethylene glycol),1,2-propanediol (propylene glycol), 1,3-propanediol, 1,4-butanediol,1,5-pentanediol, 1,3-cyclopentanediol, 1,6-hexanediol,1,4-cyclohexanediol, 1,8-octanediol and combinations thereof.

In other embodiments, the chain extender is a polyol selected frompolyethylene glycol and polypropylene glycol having molecular weights of500-10000 Daltons. Other examples include CASPOL1962 and CASPOL5004. Incertain embodiments the preferred polydiols include polydiols selectedfrom polyethylene glycol and polypropylene glycol with molecular weightsof 500-10000. In some embodiments, the crosslinker is a non-absorbablecrosslinker selected from triethanolamine (TEA), trimethylolpropane, andQUADROL (BASF Corp.). In some embodiments, the chain-extender is anon-absorbable chain extender selected from 1,4-butanediol,1,6-hexanediol, and diethylene glycol. The chain-extender or crosslinkermay be present in an isocyanate prepolymer in an amount in the range ofabout 10% to about 80% by weight of the isocyanate prepolymer.

In another embodiment, the dual putty system has improved setting andadhesiveness in aqueous environments. By nature, the isocyanatecomponent, even containing hydrolysable linkages, is essentiallyhydrophobic and will resist dissolution in aqueous systems. However,many of the diols, e.g., diethylene glycol and chain extenders, e.g.,butanediol are not resistant to water. This is true for diamines in thiscontext. It has been found that making the diol more hydrophobic byadding a hydrophobic hydrocarbon-rich residue to a polyol, e.g.,glyceryl-1 or 2-monostearate, a water resistant system is obtained. Avariation of this embodiment involves the substitution of asilicon-based moiety for the hydrocarbon-rich residue. Alternativelyhydrophobicity and setting rate in aqueous environments can be improvedthrough the use of hydrophobic fillers such as insoluble or weaklysoluble aliphatic molecules and salts thereof, including divalent salts,(eg calcium, magnesium, or zinc) of fatty acids. Also useful arecholesterol and its derivatives, as well as silated derivatives ofceramics or bone (Shimp et al., U.S. Pat. No. 7,270,813) Anotherembodiment of a water resistant, settable, dual putty system adds asmall amount of hydrophobic isocyanate to the relatively hydrophilicpolyol component resulting in a water-resistant mixture of polyolcontaining a minor amount of hydrophobic polyurethane prepolymer.

In one embodiment, the chain extender does not comprise an amino acidgroup.

Multi-Putty Embodiment

In one embodiment, the chain extender does not comprise an amino acidgroup.

The polyurethane reactants and reactions described above may be applieddirectly to the multi-putty embodiment of the invention. In thisembodiment, the compositions are produced by mixing a first puttycomposition (e.g., “Component Putty A”), which comprises one or morereactants capable of participating in chemical reactions with one ormore reactants present in a second putty composition (e.g., “ComponentPutty B”), and optionally, with reactive third, fourth, fifth, or morereactants in any number of additional putties (e.g., a third puttycomposition, a fourth composition, a fifth putty composition, or anynumber as deemed necessary or useful to those skilled in the art), toproduce a product that is harder, less flowable, and/or more cohesivethan the individual component putties. Individual component putties maybe formed by preparing a suspension of a particulate within a liquid,but may also be comprised of one or more moldable solids, e.g., awax-like material, a particulate solid, e.g., modeling clay combinedwith a moldable solid and/or a moldable solid and a liquid.

The multi-putty compositions are formed by chemical reactions whichproduce a self-hardening or increased viscosity polymer from two or morereactants (key reactive components), wherein the reactions are initiatedwhen the two or more individual component putties are mixed or combined.Mixing results in hardening or increased viscosity of the product. Inaddition to the polyurethane reactions disclosed herein other polymericreactions which may be applied to the multi-putty concept include epoxyreactions, and vinyl reactions. An epoxy adhesive or cement may beprepared by reacting a di-epoxide with an amine, such as a polyamine.Vinyl compounds, such as methylmethacrylate, may be prepared by reactingmolecules containing a vinyl or alkene group with benzoyl peroxide(radical induction) or ferric chloride (ionic induction).

For any of the reaction chemistries, of which polyurethanes are thepreferred embodiment, reactive components may be introduced inparticulate form. In such situations, the reactive components alsoprovide a bulking feature to the putty. The vehicle for the putty, insuch instances, may be non-reactive and could include any material thatdoes not detrimentally affect the reaction between the reactivecomponents (and/or second putty). Reactive components may also beintroduced as liquid vehicles. The reactive components for the componentputties will generally be in liquid form, often as a viscous liquid.

One or more of the individual component putties may be prepared as asuspension. In suspension form, particles are mixed with a liquidvehicle in proportions sufficient to produce a formable putty. Theparticles of the suspension will generally be less than 50, 40, 30 or 25microns (μm). Preferably, particles will be less than 15 microns,particle sizes of less than 10 microns, and nano particles are oftenparticularly preferred. The particles within the suspension may beinsoluble in the vehicle or the vehicle will be saturated with a solubleform of the particulate phase so that the particles themselves will notdissolve in the vehicle. Particles and liquid vehicles having similarhydrophilicity or hydrophobicity may be used in ratios of up to 80% ofparticle to vehicle (wt/wt). Other formulations useful to prepare amoldable suspension may require as little as 70, 60 or 50% particles.Some may employ 45% particles or less. The reactive molecules within theindividual component putties may be present either in particulate orvehicle form, depending on the chemistry involved.

When the chemistry permits, one or more of the individual componentputty compositions may be prepared as a moldable solid. Such solids, bythemselves, have the moldability and texture of waxes, clays or softplastics. In some cases, a softener (e.g., a non-reactive surfactant)may be included to achieve the desired moldability and to allow adequatemixing with other component putties. In instances where the reactivecomponents can be prepared as a particulate solid, it may be blendedwith a liquid or a wax-like formable material to produce the individualcomponent putty. Likewise, if the reactive components are prepared asmoldable solids, they may be softened with a liquid vehicle.

In general, the individual putty compositions of the invention may beformed by a process of combining the inventive polyol and/or a polyaminecomponents and an isocyanate or an isocyanate prepolymer component toform polyurethane and/or polyurea-based compositions. The combinationresults in a polymerization reaction that produces heat, but theincorporation of solids and/or fillers can serve as a heat sink toproduce a modulated exotherm. No adverse fumes are released during orafter mixing. The polyol component is a biocompatible,naturally-occurring or synthetic polyol, or a combination of the two, asdescribed elsewhere herein. The isocyanate component is preferably ahydrolysable diisocyanate. The process may further comprise combiningthe polyol/polyamine and isocyanate components with either water or acarboxylic acid to form carbon dioxide thus making the polymer porous.

When one or more reactive components are liquids or formable solids, itmay be desirable to mix it with an additive in the form of a particulatefiller in order to produce useful putties. In addition to viscosityadjustment, additives may be employed to affect specific features of thecomponent putty, the final product compositions described herein or thesetting or cured polymer. Properties which may be affected include, butare not limited to, component putty softness and mixability; finalproduct composition setting time, or softness (e.g., moldability),polymerized product tissue adherence, prevention of adhesion formation,osteoconductivity, osteoinductivity, inflammation, absorption, drugdelivery properties and time, among others. In some embodiments, thereactive components are pre-reacted to produce polymerized or partiallypolymerized product. This material is then reduced to particulate formthrough standard methods such as cryo-milling. These particles ofpre-reacted polymer may then be used as all or a portion of theparticulate material.

Any of the additives described herein may be added in the role of afiller to produce a putty. For bone applications, calcium salts arepreferred including calcium salts of fatty acids, phospholipids, calciumcarbonate, calcium sulfates, and calcium phosphates. Other fillers, suchas ceramics, glasses, Bioglasses, phosphate glasses, starches,cholesterols, binders, etc., may be employed. The reactive componentsfor the component putties may also be present in the form of moldablesolids such as waxes composed of fatty alcohol esters or polymers suchas poly(ethylene glycol).

For example, the process may comprise the inclusion of anosteoconductive additive such as a carbonate, e.g., calcium carbonate,magnesium carbonate, aluminum carbonate, iron carbonate, zinc carbonate,calcium bicarbonate, and sodium bicarbonate. Other osteoconductivematerials include ceramics such as substituted calcium phosphates (e.g,silicate, strontium or magnesium substitution) and glasses such asBioglass. Optionally, the process may also comprise the inclusion of asurfactant, at least one radiopaque substance, or at least one protein,or any combination of the foregoing. The process may further comprisethe inclusion of a cross-linker. In one embodiment, the cross-linker isa trifunctional castor oil-based polyol. In certain embodiments, theprocess further comprises the inclusion of one or more of bone,demineralized bone matrix, bone morphogenetic protein, calciumphosphate, siliconized calcium phosphate, calcium pyrophosphate,hydroxyapatite, poly methylmethacrylate, glass-ionomer, absorbablephosphate glass, calcium sulfate, or tricalcium phosphate, bone-likemineral (e.g., crystalline hydroxyapatite or calcium pyrophosphate). Inone embodiment, the compositions of the invention are formed by aprocess of combining an isocyanate prepolymer with a polyol orchain-extender, and a catalyst, optionally with an osteoconductivefiller, to form a poly(urethane-isocyanurate) composition. In anotherembodiment, the isocyanate prepolymer is combined with a polyol, water,and a catalyst, optionally with an osteoconductive filler, to form apoly(urethane-urea-isocyanurate) composition.

Component Putty Viscosity

Generally, compositions having a putty-like consistency may be achievedby appropriate adjustment of the liquid to solid ratio. Particle sizemay also be varied, with smaller particle sizes yielding smoother morecohesive putties. Alternatively or additionally, reactive componentswhich are liquids and/or powders may be partially reacted by limitingone or more of the reactants to produce more viscous versions of theliquid components. Softeners such as nonreactive surfactants,hydrophilic polymers such as polyethylene glycol alkyl ether, etc., mayalso be added.

When one or more reactive components are particulate solids, it may bedesirable to mix it with a liquid or moldable solid in order to producea useful putty. There are also instances independent of the physicalnature of the reactive components, where further adjustment of viscosityis required. In these instances, it is acceptable to add additionalliquid. In addition to viscosity adjustment, vehicles may be employed toaffect specific features of the component putties, final productcomposition, or the setting or cured polymer. Properties which may beaffected include, without limitation, component putty softness andmixability, final product composition setting time or softness (e.g.,moldability), polymerized product tissue adherence, prevention of tissueadhesion formation, osteoconductivity, osteoinductivity, inflammation,absorption, drug delivery properties, and time among others.

Osteoconductive Additives and Filler Materials

Non-limiting examples of osteoconductive additives that may be includedin the compositions of the invention include a carbonate (e.g., calciumcarbonate, magnesium carbonate, aluminum carbonate, iron carbonate, zinccarbonate, calcium bicarbonate, and sodium bicarbonate), bone (e.g.,demineralized bone, bone morphogenetic protein, allograft bone and/orautologous bone), calcium phosphate, siliconized calcium phosphate,substituted calcium phosphates (e.g., with magnesium, strontium, orsilicate), calcium pyrophosphate, hydroxyapatite,polymethylmethacrylate, glass-ionomer, absorbable phosphate glass,calcium sulfate, tricalcium phosphate (e.g., beta tricalcium phosphate),or any combination thereof.

In certain embodiments, the optional additive material is present in anamount of from about 0.01% to about 80% by weight of the composition. Incertain embodiments, the additive material is present in an amount of 5%to 10%, 10% to 20%, 25% to 35%, 20% to 40%, 35% to 55%, 50% to 70%, 65%to 80% or more than 80% by weight of the composition.

In certain embodiments, the optional additive is present in nano-scaleparticle sizes, but may also be present in micron or millimeter particlesizes or mixtures thereof.

Other Optional Additives

The compositions disclosed herein may also optionally comprise one ormore “cell openers.” Non-limiting examples include ORTOGEL501(Goldschmidt) and X-AIR (Specialty Polymers & Services). In certainembodiments, the cell openers are present in an amount in of from about0.1% to 5% by weight of the composition. In one embodiment, the cellopeners are present in an amount in of from about 1% to 2% or 1% to 3%by weight of the composition.

The compositions described herein may also optionally comprise one ormore antibiotics. Non-limiting examples of suitable antibiotics includebroad spectrum antibiotics (e.g., gentamicin, clindamycin,erythromycin), gram-positive and gram-negative families of antibiotics(e.g., ampicillins and cephalosporins).

The compositions of the invention may also optionally comprise one ormore local anesthetics. Non-limiting examples include lidocaine,bupivacaine, tetracaine, and ropivacaine, including the freebases theirsalts and derivatives thereof.

The compositions may also optionally comprise one or more antioxidants.Non-limiting examples of suitable antioxidants include Vitamin Eacetate, IRGANOX 1010 and IRGANOX 1035 (Ciba Geigy), and CYANOX 1790 andCYANOX 2777 (Cytec Industries). In certain embodiments, the antioxidantis present in an amount of from about 0.01% to 5% by weight of thecomposition.

In certain embodiments, a steroid-based compound, such as anintracellular messenger, may optionally be included in the compositionsdescribed herein to modulate the rate of bone growth. In someembodiments, progenitor cells optionally may be included in thecompositions of the invention.

Clinical Applications

Component putties may be mixed to relative homogeneity by hand or with amixing apparatus such as a mortar and pestle to produce the finalproduct compositions as described herein. Depending upon the specificreaction being employed, the final product composition will begin toharden over time. During this phase, the compositions may be applied tothe body for its intended use. In some embodiments, the compositions maybe applied to bleeding bone to act as a hemostatic tamponade. In otherembodiments, the compositions may be applied as an adhesive, e.g., tostabilize a bone fracture or reapproximate a sternotomy. In otherembodiments, the compositions may be applied as a bone void filler toaid in the healing of bone defects, as a bone cement to fill gaps in theskeletal system, result in skeletal fusion or aid in the adhesionbetween bone segments, fragments and/or metallic hardware. Thecompositions described herein can be custom shaped by a clinician tocreate form fitting fixation devices such as sheets, rods, wraps orother support structures that may be anchored by plates, sutures orscrews.

Hardened Polymer

A hardened polymer, preferably containing an osteoconductive filler, maybe ground to a fine powder and used, as such, or converted into a puttyby mixing with a suitable vehicle, to fill bone voids and otherorthopedic defects. The component putty concept could be used duringmanufacturing as an alternative to “conventional” polymerization usingliquids and fillers to form fully cured materials due to the improvedhandling properties that eliminate liquid and taffy phases ofpolymerization.

Water

In certain embodiments, the compositions of the invention contain noadded water. In some embodiments, the compositions are anhydrous. Incertain embodiments where there is no added water, water maynevertheless be present in small amounts. For example, certaincommercially-available polyols comprise a mixture of the polyol and asmall amount of water. In addition, certain optional particulatematerials as described herein, such as calcium carbonate may comprisebound water. Formulating the compositions in an atmosphere that containsmoisture may also result in the incorporation of water into thecompositions. In certain embodiments of the present invention, thecompositions are prepared under a nitrogen purge that comprises adesired amount of moisture, thereby controlling the water content of thecompositions. In other embodiments, water may be added to thecompositions during the process of their formation from the componentparts. In other embodiments, the compositions are prepared underessentially water-free conditions with anhydrous components such thatthe resulting compositions are essentially anhydrous.

In certain embodiments, water is present in the compositions being madein an amount from at least about 0.01% to about 3% by weight of thecomposition. In certain embodiments, water is present in an amount offrom about 0.05% to 1%, from about 0.05% to 1.5%, from about 0.1% to 1%,from about 0.1% to 1.5%, from about 0.1% to 2%, from about 1% to 2%, orfrom about 2% to 3%.

Particulate Materials

Both the putty- and non-putty compositions of the invention may containoptional particulate materials. In one embodiment, the particulatematerial is an osteoconductive material. In certain embodiments, theparticulate material supports or promotes the growth of bone at theapplication site. In certain embodiments, the mean particle size of theoptional particulate material is in the micron or submicron range. Inone embodiment, the mean particle size is from about 0.001 to 0.100microns, from about 0.100 to 5 microns, from about 5 to 100 microns,from about 5 to 500 microns, or from about 500 to 1000 microns.

In one embodiment, the optional particulate material is a carbonate orbicarbonate, e.g., calcium carbonate, magnesium carbonate, aluminumcarbonate, iron carbonate, zinc carbonate, calcium bicarbonate, andsodium bicarbonate, or any combination thereof. In one embodiment, theoptional particulate material is bone (e.g., demineralized bone, bonemorphogenetic protein, allograft bone, and/or autogenous bone), calciumphosphate, siliconized calcium phosphate, substituted calcium phosphates(e.g., with magnesium, strontium, or silicate), calcium pyrophosphate,hydroxyapatite, polymethyl methacrylate, glass-ionomer, absorbablephosphate glass, calcium sulfate, tricalcium phosphate (e.g., betatricalcium phosphate), or any combination thereof. Other examplesinclude poly ether ether ketone (PEEK), REPLACE (Cortek, Inc.), EXPANCEL(Akzo Nobel). In other embodiments, the particulate material is aceramic such as substituted calcium phosphates (e.g, silicate, strontiumor magnesium substitution) or a glass such as bioglass. In someembodiments, the particulate material is one or more of calcium sulfate,calcium phosphosilicate, sodium phosphate, calcium aluminate, calciumphosphate, hydroxyapatite, demineralized bone, or mineralized bone. Theoptional particulate material, when present, may comprise any one ormore of the materials listed in the embodiments above. In oneembodiment, the particulate material, if present in the composition,does not comprise calcium carbonate.

In certain embodiments, the optional particulate material is present inan amount of from about 0.01% to about 10% by weight of the composition.In certain embodiments, the optional particulate material is present inan amount of 0.10% to 10%, 1% to 10%, or 5% to 10%. In otherembodiments, the optional particulate material is present in an amountof from about 10% to about 20% by weight of the composition, or fromabout 20% to 30%, about 30% to 40%, about 40% to 50%, about 50% to 60%,about 60% to 70% or about 70% to 80% by weight of the composition.

Foaming Agents

In certain embodiments, an optional foaming agent may be included in theprocess of forming the compositions of the invention, for example tomodulate pore size. Carboxylic acids may act as foaming agents byreacting with isocyanates to form carbon dioxide (and the correspondingamide). Non-limiting examples of carboxylic acids that can be used inthis manner are benzoic acid, malic acid, and succinic acid. In certainembodiments, the compositions of the invention are formed by a processof combining a polyol and/or polyamine, a polyisocyanate, and acarboxylic acid. In one embodiment, the compositions formed with acarboxylic acid do not contain water. In another embodiment, thecompositions formed with a carboxylic acid do not contain added water.In another embodiment, albumen is used as a foaming agent with orwithout sodium alginate to form the compositions of the invention. Inanother embodiment, hydrogen peroxide is used as a foaming agent to formthe compositions of the invention.

Catalyst Component

In certain embodiments an optional catalyst is added, e.g., to thepolyol that is combined with the isocyanate to form the compositions ofthe invention. In certain embodiments, at least one catalyst is presentin an amount sufficient to ensure that the polymerization reactions haveproceeded to completion before the compositions are placed within thebody of a mammal. Non-limiting examples of catalysts include a tertiaryamine (e.g., DABCO 33LV, Air Products, Inc.) and organometalliccompounds such as, for example, stannous octoate, and dibutyl tindilaurate (e.g., DABCO T12, Air Products, Inc.). In certain embodiments,the catalyst may remain in the composition after its formulation andcuring, e.g., as a monomer that is present in the matrix of thesolidified form of the composition. A non-limiting example of such acatalyst is N,N,N′-Tri(2-hydroxylpropyl)-N′-hydroxyethyl ethylenediamine (POLY-Q-40-800, Arch Chemicals, Inc.).

In certain embodiments, the catalyst is present in the polyol in anamount of from about 0.05% to about 0.5% by weight of the polyol. Incertain embodiments, the catalyst is present in an amount of from about0.15% to about 0.4% by weight of the polyol.

Optional Surfactant Component

In certain embodiments, an optional surfactant is included in theprocess of forming the compositions of the invention in order to controlthe porosity of the composition including the size and/or shape of poreswithin the composition. Non-limiting examples of suitable surfactantsinclude DABCO DC 193 and DABCO DC 5241 (Air Products, Inc.), MAXEMUL6106 and MAXEMUL 6112 (Uniqema), and silicone surfactants (e.g., thoseavailable from Struktol Corp.).

Radiotransparent/Radiopaque Component

In the multi-putty embodiment, in many instances the filler used will beradiopaque (eg calcium phosphate granules) and impart radioopacity tothe hardened formulation. In certain other embodiments, an optionalradiotransparent and/or a radiopaque substance is included in thecompositions of the invention. Non-limiting examples of aradiotransparent substance include air, nitrogen gas, carbon dioxide,and oxygen gas. Non-limiting examples of a radiopaque substance includeceramic particles (eg calcium phosphate) barium sulphate (BaSO₄) andzirconium dioxide (ZrO₂). Examples of commercially available radiopaquesubstances include LIPIODOL, HYPAQUE, and OMNIPAQUE. The at least oneradiotransparent substance and/or radiopaque substance, when present, ispresent in the compositions in an amount of from about 5% to about 30%by weight of the composition, and, in certain embodiments, from about10% to about 20% by weight of the composition.

Protein Component

The compositions of the present invention may optionally comprise one ormore bioactive proteins, peptides, or polypeptides. Preferably, the oneor more bioactive proteins, peptides, or polypeptides is active in thestimulation of bone growth. Non-limiting examples of suitable proteinsinclude collagen, OP1 (Stryker Homedica), INFUSE (Medtronic Corp.), orany recombinant bone morphogenic protein. Preferably, the one or morebioactive proteins, peptides, or polypeptides is non-reactive with theother components of the composition, allowing it to be included at anypoint during the formulating process. Thus, when present, the one ormore peptides is not incorporated into the polymer backbone, but insteadis either embedded in the polymer matrix, dispersed in the composition,or adherent to the surface of the composition.

The one or more bioactive proteins, peptides, or polypeptides may beincorporated within the compositions for example, by inclusion in theprocess of combining the isocyanate component and the polyol/polyaminecomponent. In this way, the one or more bioactive proteins, peptides, orpolypeptides is dispersed throughout the composition. Alternatively, theone or more bioactive proteins, peptides, or polypeptides may be addedafter all other components have been combined, preferably from about 10minutes to about 45 minutes after combination of the other components.In this way, the one or more bioactive proteins, peptides, orpolypeptides adheres to an outer surface of the composition.

Optional Light- or Photo-Initiators

The compositions of the present invention may comprise light- orphoto-initiators. Non-limiting examples of suitable light- orphoto-initiators include 24650-42-8 (Loctite Corp). In a preferredembodiment, the light- or photo-initiators are included in compositionsmade from unsaturated components, e.g., isocyanate prepolymers havingone or more double bonds, polyols having double bonds, or adducts formedfrom reactions between isocyanates and acrylates.

A photo- or light-initiator may be incorporated into the compositions,for example, by combining with a liquid component (e.g., an isocyanate,a polyol or polyamine, a chain-extender or crosslinker).

In certain embodiments, the compositions comprising a photo- orlight-initiator solidify at an accelerated rate, e.g., in the range offrom about 1 to 5 minutes or 1 to 10 minutes after exposure to asuitable energy source (e.g., a suitable light source).

Other Optional Additives

The compositions of the invention may also optionally comprise one ormore “cell openers.” Non-limiting examples include ORTOGEL501(Goldschmidt) and X-AIR (Specialty Polymers & Services). In certainembodiments, the cell openers are present in an amount in of from about0.1% to 5% by weight of the composition. In one embodiment, the cellopeners are present in an amount in of from about 1% to 2% or 1% to 3%by weight of the composition.

The compositions of the invention may also optionally comprise one ormore antibiotics. Non-limiting examples of suitable antibiotics includebroad spectrum antibiotics (e.g., gentamicin, clindamycin,erythromycin), gram-positive and gram-negative families of antibiotics(e.g., ampicillins and cephalosporins).

The compositions of the invention may also optionally comprise one ormore local anesthetics or analgesics. Non-limiting examples includelidocaine, bupivacaine, tetracaine, and ropivacaine. Further examplesinclude benzocaine and fentanyl (a potent non-opioid).

The compositions of the invention may also optionally comprise one ormore anti-inflammatory substances such as the non-specific ibuprofen andaspirin, or the COX-2 specific inhibitors such as rofecoxib andceleboxib.

The compositions of the invention may also optionally comprise one ormore antioxidants. Non-limiting examples of suitable antioxidantsinclude IRGANOX 1010 and IRGANOX 1035 (Ciba Geigy), and CYANOX 1790 andCYANOX 2777 (Cytec Industries). In certain embodiments, the antioxidantis present in an amount of from about 0.01% to 0.5% by weight of thecomposition.

In certain embodiments, a composition of the invention further comprisesa colorant. Non-limiting examples of suitable colorants include gentianviolet, D&C Violet #2, and D&C Green #6.

In certain embodiments, a steroid-based compound, such as anintracellular messenger, may optionally be included in the compositionsof the invention to modulate the rate of bone growth. In someembodiments, progenitor cells optionally may be included in thecompositions of the invention.

EXAMPLES

The following example describes the preparation of a number ofmultiputty compositions using a resorbable polyurethane system. Theputties were made by mixing either a liquid isocyanate or a polyolsolution with particulate calcium salts. Enough calcium salt was addedto establish suitable handling properties. For all isocyanate putties,[5-[2-[2-(4-Isocyanatobenzoyl)oxypropanoyloxy]-ethoxy]-1-methyl-2-oxo-pentyl]-4-isocyanatobenzoate,also referred to as “ALD”, was the isocyanate used. All polyol basedputties used a polyol solution that consisted of polycaprolactone diol(molecular weight=530 KDa) and 1,4-butane diol in a 40%:60% molar ratio,respectively.

In one experiment, three different filler types, HA-TCP, calciumcarbonate, and anhydrous dibasic calcium phosphate (at amounts rangingbetween 50-70%) and concentration of isocyanate and polyol/extendermixtures were varied. The compositions also varied the filler particlesize, i.e., nanometer, micrometer (small), and millimeter (medium).

For formulations comprising calcium carbonate, 50% of projected weightpercent calcium carbonate (Component C) was weighed in a plastic cup.Isocyanate (Component A) was added to the cup and mixed with the calciumcarbonate. Another 20% of calcium carbonate (70% of total sample weight)was added to the cup and mixed for 2-3 minutes to obtain a uniformcomposition. Caprolactone 530 and butanediol (Component B) was thenadded to the mixture and stirred for another minute. This mixture wasthen applied to a wet bone surface. It was spreadable for up to 1-2minutes, after which it transformed into a cohesive hard putty that wasno longer spreadable.

For formulations with HA-TCP, 70% of projected weight percent HA-TCP wasweighed in a plastic cup. Isocyanate was added to the cup and mixed fora minute to obtain a uniform composition. Caprolactone 530 andbutanediol was then added to the mixture and stirred for another minute.After 2-3 minutes, the mixture was applied to a wet bone surface. It wasnot spreadable and was more granular compared with calcium carbonate.After 5-6 minutes, it transformed into a cohesive putty. In general,calcium carbonate (up to 70%) performed better in spreadability andadhesion to bone compared with HA-TCP. Finer particle sizes appeared towork better.

In another experiment, the hydrophilicity and molecular weight ofpolyol/extender combinations (Component B) were varied, with theobjective of extending putty composition pot life. Here, calciumcarbonate was mixed with isocyanate, forming a composition having aputty-like consistency. Pluronic L-35 (much more hydrophilic thancaprolactone 530) and butanediol was then added and mixed for another 2minutes to obtain a uniform composition. After 3 minutes, it was viscousand sticky. It was then applied on a wet bone surface and was spreadablefor up to 20 minutes. The reaction of Pluronic with isocyanate wasslower than with Caprolactone 530. Additional experiments using lessPluronic were performed, with Caprolactone 530 as the polyol mixture. Toimprove rigidity, lower molecular weight PEGs were also used insubsequent experiments.

In another experiment, prepolymers/salts were used as a hemostat,followed by isocyanate/salt/polyol/extender mixtures as adhesiveadherents to previously applied hemostats. Here, calcium carbonate (70%of total projected sample weight) was weighed in a plastic cup.Isocyanate was added to the cup and mixed for 2 minutes to obtain auniform composition. This mixture was then applied to a wet bone.Spreadability and adhesion appeared to be good. Component B(Caprolactone 530 and butanediol without salt) at a 5% concentration wasthen added to the mixture and mixed for another minute to form aprepolymer. After 3 minutes, the mixture turned into a coherent puttythat was hard and non-spreadable. It was found that component A(isocyanate) in combination with a filler (calcium carbonate) can beused as a bone hemostat. Further experiments were conducted to determinethe efficacy of the prepolymer concept by varying the isocyanate/polyolratio or combining a Pluronic with Caprolactone 530 to reduce the rateof reaction.

General Putty Observations

Table 1 provides a summary of the putty compositions disclosed herein.All ALD putties displayed excellent hand feel, holding their shape uponstorage and did not stick to gloves. All putties formed possessed asmooth texture with little evidence of calcium salt granules, regardlessof composition or size. Polyol putties displayed varying amounts ofcreep upon storage depending on composition. Options for reducing creepincluded increasing the particulate calcium salt content. Alternatively,viscosity of the liquid component was adjusted through the use of aviscosity-increasing partial reaction of the liquid components. Thisstrategy is exemplified in example #12 where a partially pre-reactedputty was used.

TABLE 1 Exemplary putty compositions Liquid reactive Component PuttyPutty C # Putty components (wt %) Additive Filler (wt %) ObservationsObservations 1 A ALD (27%) CaCO₃ (73%) Workable for B Polyol (21%) CaCO₃(79%) Excellent handling about 10 min.; properties appeared fullyhardened after 24 hrs; final putty was hard and stiff. 2 A ALD (67%) HA(nanocrystals) (33%) Putty hardened after Workable for storage overnightin about 10 min.; a sealed contained, appeared fully likely due toreaction hardened after between HA and ALD 24 hrs with B Polyol (57%) HA(nanocrystals) (43%) Poor handling slightly sticky properties (crumbly)feel during hardening. 3 A ALD (39%) DCP (61%) Workable for B Polyol(35%) DCP (65%) Poor handling about 10 min.; properties (crumbly)appeared fully hardened after 24 hrs; final putty was hard and stiff. 4A ALD (48%) β-TCP (5 μm) (52%) Workable for B Polyol (43%) β-TCP (5 μm)(57%) Good handling about 10 min.; properties appeared fully hardenedafter 24 hrs; final putty was hard and stiff. 5 A ALD (49%) β-TCP(nanocrystals) (51%) Workable for B Polyol (43%) β-TCP (nanocrystals)(57%) Good handling about 10 min.; properties appeared fully hardenedafter 24 hrs; final putty was hard and stiff. 6 A ALD (27%) HA/TCP(250-630 μm) (51%) + Workable for β-TCP (5 μm) (22%) about 10 min.; BPolyol (24%) HA/TCP (250-630 μm) (49%) + Good handling appeared fullyβ-TCP (5 μm) (27%) properties hardened after 24 hrs; final putty washard and stiff. 7 A ALD (37%) TCP (100-300 μm) (43%) + Workable forβ-TCP (5 μm) (20%) about 10 min.; B Polyol (43%) TCP (100-300 μm)(35%) + Good handling appeared fully β-TCP (5 μm) (22%) propertieshardened after 24 hrs; final putty was hard and stiff. 8 A ALDHA/TCP(250-630 μm) + Good handling Workable for DCP properties about 10min,; B Polyol HA/TCP(250-630 μm) + Good handling appeared fully DCPproperties hardened after 24 hrs; final putty was hard and stiff. 9 AALD HA/TCP(250-630 μm) + Good handling Workable for CaCO₃ propertiesabout 10 min.; B Polyol HA/TCP(250-630 μm) + Good handling appearedfully CaCO₃ properties hardened after 24 hrs; final putty was hard andstiff. 10 A ALD (27%) HA/TCP(250-630 μm) (51%) + Workable for β-TCP (5μm) (22%) about 10 min.; B Polyol (28%) HA/TCP(250-630 μm) (55%) + Poorhandling appeared fully HA (17%) properties (crumbly) hardened after 24hrs; final putty was hard and stiff. 11 — ALD (26%) HA/TCP (250-630 μm)(51%) + Good handling Not combined β-TCP (5 μm) (13%) properties; doesnot to form stick to gloves; putty polyurethane. holds shape; largegranules were not apparent by feel through gloves 12 A ALD (27%)HA/TCP(250-630 μm) (51%) + Workable for β-TCP (5 μm) (22%) about 10min.; B ALD (27)% + β-TCP (5 μm) (37%) Good handling appeared fullypolyol (36%) properties, similar feel hardened after to ALD putties;does not 24 hrs; final stick to gloves; putty putty was hard holds shapelike ALD and stiff. No putties apparent difference than using straightALD and polyol putties to form polyurethane. TCP = Tricalcium phosphateCaCO₃ = calcium carbonate β-TCP = beta tricalcium phosphate HA =hydroxyapatite DCP = Dicalcium phosphate anhydrous HA/TCP =Hydroxyapatite/beta tricalcium phosphateMixed Putty Observations

Polyurethane/calcium salt composites were formed by combining isocyanateand polyol putties (or in one case an isocyanate and prepolymer putty)in an approximately 1:1 molar ratio of isocyanate to polyol. Compositeswere formed using putties with the same calcium salt compositions ordifferent compositions. After mixing two reactive putties, the combinedputty is exothermic, softens slightly and becomes slightly sticky,before hardening over time. All individual putties are spreadable andworkable over cut bone surfaces. Combined putties are spreadable overcut bone surfaces or workable for a period of time prior to hardening.No major differences were apparent in the working time for allcomposites formed.

Clinical Example A Sternotomy Hemostasis Device and Cement

An absorbable dual putty settable polyurethane system was prepared bymixing the following components that were stored separately inmoisture-free containers:

Putty A:

Absorbable diisocyanate (ALD) 27.0% Calcium carbonate 71.6 Caprolactone530/16 parts 1.4Putty B:

Caprolactone 530 16.0% Butanediol 5.0 Calcium carbonate 77.6 ALD 1.4

In preparation for a coronary artery bypass procedure, the thoraciccavity was opened using a midline incision of the sternum. Putty B wasmanually applied to both edges of the sawed sternum to control bleeding.Putty B, which is not a reactive hemostat, stops bleeding by blockadingcut bone channels, through which blood escapes, causing static bloodbehind the putty to spontaneously clot (tamponade).

Following the surgical procedure which lasted several hours, the edgesof the cut sternum are cleaned with gauze sponges and examined for anyareas of re-bleeding to which, if found, additional Putty B was appliedto ensure complete hemostasis.

A bead of Putty A was deposited along the entire length of one edge ofthe cut sternum which was then approximated to the other edge andpressed together. Stainless steel wire was placed to firmly hold thesternum edges together while the polyurethane cured overnight andthereby helps prevent painful stress-related shear motion. Healing bonegrowth occurred as the polyurethane was absorbed.

Clinical Example B Sternotomy Hemostasis Device and Cement

The same dual putty system prepared for Clinical Example A is used inClinical Example B. In this example, Putty A and Putty B were mixed bykneading and applied to the split sternum as a hemostatic agent. Afterhemostasis was achieved, the surgery was carried out and, at theconclusion, a fresh bead of the two-putty mixture was applied to oneedge of the sternum before the two edges were reapproximated andreinforced with wire or other hardware. Adhesion to the previouslyplaced hemostatic polyurethane was satisfactory.

EQUIVALENTS

Those skilled in the art will recognize or be able to ascertain using nomore than routine experimentation, many equivalents to the specificembodiments of the invention described herein. Such equivalents areintended to be encompassed by the following claims.

All references cited herein are incorporated herein by reference intheir entirety and for all purposes to the same extent as if eachindividual publication or patent or patent application was specificallyand individually indicated to be incorporated by reference in itsentirety for all purposes.

The present invention is not to be limited in scope by the specificembodiments described herein. Indeed, various modifications of theinvention in addition to those described herein will become apparent tothose skilled in the art from the foregoing description and accompanyingfigures. Such modifications are intended to fall within the scope of theappended claims.

What is claimed is:
 1. A sterile, body-absorbable composition comprisingtwo or more separate reactive putties which can be hand mixed or kneadedtogether to form a homogenous settable polyurethane or polyureaurethaneputty composition which hardens into its fully cured solid form at roomtemperature and body temperature, the first putty comprising one or moreisocyanates and a particulate material in amounts sufficient to producea putty, the second putty comprising one or more polyols and aparticulate material in amounts sufficient to produce a putty, such thatthe amount of the particulate material in the homogenous settablecomposition is in a range of from 50-60%, 60-70%, or 70-80% of thecomposition by weight, wherein the one or more polyols is selected fromhydroxyl terminated homopolymers or copolymers of glycolide, lactide,p-dioxanone, trimethylene carbonate and/or caprolactone, polyethyleneglycol, and a random or block copolymer of ethyelene oxide and propyleneoxide, wherein the particulate filler material is selected from calciumphosphate, siliconized calcium phosphate, calcium phosphate substitutedwith magnesium, strontium, or silicate, calcium pyrophosphate,hydroxyapatite, polymethyl methacrylate, glass-ionomer, absorbablephosphate glass, calcium sulfate, tricalcium phosphate, or anycombination thereof, and each putty optionally comprises one or moreadditive components.
 2. The composition of claim 1, wherein the one ormore isocyanates is an aromatic isocyanate, an aliphatic isocyanate, acycloaliphatic isocyanate, or an adduct of an isocyanate.
 3. Thecomposition of claim 2, wherein the one or more isocyanates is anaromatic di- or polyisocyanate-having at least one hydrolysable linkagebridging at least two of the aromatic rings.
 4. The composition of claim3, wherein the hydrolysable linkage is derived from glycolic acid,lactic acid, or a polycaprolactone.
 5. The composition of claim 1,wherein the one or more polyols is degradable.
 6. The composition ofclaim 1, wherein the one or more polyols is selected from apolycaprolactone-co-glycolide or a polycaprolactone-co-lactide, orcombinations thereof.
 7. The composition of claim 1, wherein the secondputty further comprises one or more polyamines selected from a primaryamine, a secondary amine, or a hindered amine.
 8. The composition ofclaim 7, wherein the one or more polyamines is selected from ethylenediamine, 1,2-propane diamine, 1,3-propane diamine, butane diamine,cyclopentane diamine, cyclohexane diamine and hexamethylene diamine. 9.The composition of claim 1, wherein the one or more additive componentsin each individual reactive putty comprises a carbonate or bicarbonateselected from calcium carbonate, sodium carbonate, magnesium carbonate,aluminum carbonate, iron carbonate, zinc carbonate, calcium bicarbonate,sodium bicarbonate, a bicarbonate of magnesium, aluminum, iron, or zinc,embedded particles of bone, demineralized bone, bone morphogeneticprotein, and combinations thereof.
 10. The composition of claim 9,wherein the one or more additive components in each individual reactiveputty comprises a carbonate or bicarbonate selected from calciumcarbonate, sodium carbonate, magnesium carbonate, aluminum carbonate,iron carbonate, zinc carbonate, calcium bicarbonate, and sodiumbicarbonate, or any combination thereof.
 11. The composition of claim 9,wherein the one or more additive components in each individual reactiveputty comprises embedded particles of bone, demineralized bone, bonemorphogenetic protein, or any combination thereof.
 12. The compositionof claim 1, further comprising one or more additives selected from anantioxidant, an antibiotic, an antimicrobial, and an anesthetic.
 13. Thecomposition of claim 1, wherein the two or more putties, after mixingform a composition that develops mechanical properties suitable for invivo use as a bone cement, bone substitute, adhesive, and/or bonehemostatic agent.
 14. The composition of claim 1, wherein the two ormore putties, after mixing but prior to fully curing, form a compositionthat adheres to bleeding bone and the bleeding is stopped within about10 minutes after application of the composition.
 15. The composition ofclaim 13, wherein the freshly mixed composition exhibits a low,physiologically acceptable exotherm.
 16. The composition of claim 1,wherein the fully cured solid form has an average pore size in the rangeof from about 5 to 700 microns.
 17. A package or article of manufacturecomprising the components of the composition of claim
 1. 18. The packageor article of manufacture of claim 17, wherein the components aresterile or sterilizable.
 19. A method of stabilizing a bone fracture orreapproximating a sternotomy, the method comprising the steps of mixingor kneading together the two or more putties of claim 1 to form asettable polyurethane or polyureaurethane composition, applying thecomposition to the bone fracture or the sternum, and allowing thecomposition to harden into its fully cured solid form.
 20. Thecomposition of claim 1, wherein the tricalcium phosphate is betatricalcium phosphate.